The three major objectives of this proposal are as follows: 1) to explore the environmental factors associated with hyperactivity and with the process of being identified as hyperactive; 2) to study hyperactive children and their treatment programs over time and 3) to generate and test hypotheses about the relationship of social and cognitive developmental factors to hyperactivity. We have collected data on a representative population of 5,000 public and private school pupils which includes measures of pupil behavior, self concept, peer relationships, school achievement, classroom environments and teacher attitudes. Our hyperactive sample (N equals 278) includes children from these same schools who have been medically identified as hyperactive and satisfy additionally rigorous operational criteria. A sample of children matched on behavioral characteristics, sex, and age (N equals 129) and a random sample (N equals 129) from the representative population provide contrasting data for our investigation. We have parent consent for all pupil subjects, as well as demographic information and measures of environment and attitudes. Complete medical histories are available for all of the hyperactive subjects. Our existing data base provides the measures for the environmental factors and the identification process study. During the proposed period, we will collect annually measures of hyperactivity, achievement, self concept, and cognitive and social development from these same hyperactive, matched, and random control subjects. In addition, we will assess home and school environments and parent and teacher attitudes. The physician of each hyperactive child will provide annual medical data, including information on the course of treatment regimen. The assessment of hyperactivity will include multiple measures of activity level, impulsivity, attention-distractibility, aggression and sociability. Using these dependent measures, factors associated with changes in behavior will be identified.